Carburetor



Patented Apr, 2, 3931 GLES LAWRENCE SEOKES, OF LDS ANGELES, CALE'ORNI, ASSIGNOE T@ CUMIS B;

GAME, TRUSTEE, OF GLMUE, ELLCNOIS CABBUBE'EOE Application filed January 5, 1928. Serial Ne. 79,408.

My invention relates to improvements in automatic uel regulators for supplying fuel in the proper amounts under all conditions to an internal combustion engine.

The principal 'object of my invention isto automatically provide an internal combustion engine, in accordance with its suction, with the proper amount of fuel for starting, idling, accelerating and in general for all variable speed conditions.

Another object of my invention is to utilize at times the engine temperature for finerregu-` lation.

Another object of my invention is to provide an automatically regulated carburetor for internal combustion engines.

This invention embodies in a novel form some of the principles shown and described in my co-pendingapplications Ser. Nos. 626990,

filed March 22, 1.923; 644,925, filed June 12, 1923; 676,864, filed November 24., 1923; 715,912, filed May 26, 1924:; 56,513, filed September 15, 1925; 67,864, filed November 9, 1925.

In the drawings Fig. 1 is a vertical crosssection of a carburetor embodying my invention.

j Fig. 2 is a vertical section of a portion of a carburetor, with parts broken way;

F ig. 3 is a horizontal section of the outer, intermediate and inner tubes, showing th plg in position ther-ein; v

ig. 4,is a side elevation of an internal combustion engine shown more or less dia- 35 grammatically, and showing the invention in position thereon, with parts in section;

Fig. 5 shows a section similar to Fig. 1, and disclosing a modified form of Construction, with parts brokenaway;

Fig, 6 is a transverse vertical section of the air passage, taken through the venturi and showin a modified form of construction;

Fig. is a horizontal, vertical section of the air passage, showing a further modified 46 form of Construction; and' Fig. 8 is a longitudinal, vertical section of the ainpassage, anterior of the venturi.

Referrng to the drawings, a carburetor is shown which includes a mixing chamber 1 of circular cross-section wherein is cast a cross piece 2. A flange 3 is adapted to connect the carburetor 'as a whole to the intake passage 3a of an internal combustion engine SI andan air passage 4 opens the mxing chamber 1 to atmosphere, the passage of which is controlled by a butterfiy throttle i valve 5'. ,The lower part of the mixing chamberand air passage forms a circular cover 6 adapted to enclose a bowl 7 containing liquid fuel supplied thereto in any well known manner through a passage 7b controlled by a valve (not shown) actuated by fioat &when a pret determined level of liquid fuel A-A has been attained therein. Inasmuch as the Construction of the float and valve mechanism in a 5.5;

carburetor fioat chamber is well known, it is `unnecessary to enlarge thereon as the same forms no specific part of my invention.

l`he cover 6 is held in air tight relation with bowl 7 by means 'of screws 9 and a gasket 10. i Communication between the chamber 1 and bowl 7 is provided by a small passage 11 and atmosphereis admitted to bowl 7 through a passae 12 adjustably controlled by a valve 13. lternatively passage 12 may communi cate direct with passage 11 so that vapors may not be drawn oli from the fuel in bowl 7.

Centrally of the chamber 1 and bowl 7 are placed a series of concentric tubes comprising an outer tube 14, an intermediate tube 15 and a central tube 16, the tubes being sup ported one between the other, by the cross piece 2 and the coverB. A passage 17 for air is drilled through one arm of the cross piece 2, the passage of air therethrough being 86 adjustably controlled by a valve 18 and passage 17 connects through an orifice 19 to the interior of pipe 14, the lower end of which is closed and does not extend into thebowl 7. g Pipes 15 and 16 extend through cover 6 99 close to the bottom ofbowl 7, the lower end of pipe 15 containing an enlar 'gement 20 wherein is placed an upwardly raising light check valve 21 having a small central orifice 22. The lower end of pipe 16 is closed, its upper end extending to' the throat of a venturi 23 and a series of small orifices 24 of predetermined size and spaced apart predetermined distances are drilled in pipe 16 to communicate with the interior of pipe 15. A series of' valve 29, the same being mounted on an insulated block 30 interiorly of air passage 4.

A pipe 31 connects passage 4 to atstove 32 surrounding the exhaust pipe 33 of the engine 3?) to which the carburetor as a whole is'attached for 'the purpose of supplying heated air to' aid in the Vaporization of the liquid fuel drawn from bowl 7 in a well known* manner. i

The operation of the ,carburetor with automatic fuel regulation is as follows: 4

If throttle 5 be closed and it is desired to start the engine at very low temperatures, the discharge end of passage 26 will be wide open due to the action of thermostat 28. Upon cranking the engine, the suction of the same will be applied through chamber l to the discharge end of tube 16 and through orifice 11 A to the bowl '7. Thecranking suction thus engendered will cause liquid fuel to be drawn in comparatively large Volume through orifices 24 below the normal liquid level A-A. At the same time let itbe assumed that the suction applied through orifice 11 is suflicient only to draw the liquid fuel in tube 15 down to the level B-B, this being made possible by the air adjusting screw 13. The cranking of the engine will continue whereby liquid fuel will be drawn through orifices 24 in suflicient quantity to ensure a quick start, the same carbureting the air passing through anyof the orifices 24 above the liquid level B-B in pipe 15 and also the' small portion of air passing through throttle 5 and orifice s soon as the engine starts the vacuum applied through chanber 1 and the said i orifices .will suddenly increase whereby the liquid level in tube 15 Will recede to the line C-C permitting only sufficient liquid fuel to pass through the lowermost orifice 24"for idling the engine. Should this amount of fuel be insufl icientto keep the engine idling, the speed of the engine will drop`o whereby the Vacuum will drop off and therefore the fuel in tube 15 will rise and .cover one or more of the orifices 24 whereby additional liquid fuel will be supplied the engine to keep it running.

' During this'time of starting the engine, substantally atmospheric pressure will prevail anteriorly of throttle 5 and therefore atnospheric pressure will substantially pre- Vail interiorly of pipe 14 and also of pipe 15 because the air may pass readily through orifices25 from passages 17 and 26, the uppermost orifi'ce 25 being relatively large for passing air only.

If a higher engine speed is desired, the throttle 5 will be opened a predetermined distance whereupon the pressure in chamber 1 and bowl 7 will increase to the end that liquid fuel will rise in pipe 15 a predetermined, .amount and supply additional' fuel through a predetermined additional number ofthe orifices 24. l/Vhen' 'throttle 5 is further openedto wide open, the 'suction in 26 .will

be inreased to a maximum whereby the liq-.

uid fuel in pipe 15 will be raised to cover the orifices 24, with the' possible exception of one, and will be discharged into passage 26 and thus into chamber-l through a predetermined number of orifices 25. In this manner a proper proportion of fu el t'o air is main tained for Operating the engine to which the 'carburetor is attached. It will be noted that the liquid fuel being drawn through orifices 25 will be mixed with air passing through 17 and thus the delivery and carburetion thereof is accelerated. As the engine warns up, the height to which the liquid fuel will rise 'in tube 15 is automatically reduced by the action of thermostat 28 and Valve 29 which is .so regulated that the flow of heated air passed will decrease the mixture strength with increasing engine temperature until an optimum mixture is being supplied.

If throttle 5 be closed and it is dcsired to suddenly accelerate'the engine, throttle 5 will be thrown wide open whereupon' thevacuum in bowl 7 will be reduced to a minimum and a vacuum in passage 26 will be increased Very largely whereby the'liquid column in tube 15 will riserapidly to the uppermost orifice 25 and thus provide-a large Volume of liquid fuel for quick acceleration and immediately thereafter, the inertia of -the column being spent, the liquid-fuel in pipel will recede to discharge the correct quantity of liquid fuel through other orifices 25 and 24.

From the operation described, it will be seen 'that I have provided what for convenience of description will be termed a manometer member which includes a constant level arm in the bowl 7 and a variable level arm in tube 15 and I take advantage of the difierentials shown in engine vacuums for Operating the manometer member to give correct fuel proportions under all conditions of engine suction, according to the throttle soaieo r opening. Normally the vacuum in bowl 7 may vary from atmosphere at quick acceleration to four inches of gasoline when idling, but of course these proportions will change with different designs for dilerent engines and I can maintain any desired difierential pressure between the manometer arms up to several inches of nercury.

The sizes of the orifices and distances therebetween are purely a matter of trial for each type of engine, but in general said distances are pretc-rably sufiicient to prevent excess feed through the orifices under very small fiuctuations of liquid in the manometer member arm 15. This can be arranged to any degree by extending the tubes and 16 even through the bottom of bowl 7 in a suitable extension thereof.

Tt will be noted that bowl 7 is substa'ntially always under a slight vacuum and also that the rise of liquid fuel'in tube 15 at ac-. celeration and otherwise for discharge through orifices is due to an increase in suction in 26 and not essentially to a decrease in suction in bowl 7 this decrease being sufficient only to permit the liquid fuel to rise in tube 15 not more than the normal level A-A, but the inertia of the reciprocating liquid fuel column will cause it to rise higher.,

Tt should also be noted that liquid fuel is always in both arms of the manometer member, i. e. in the tube 15 and bowl 7 and at no time is the fuel totally withdrawn from tube 15. At the same time the level in bowl 7 is maintained substantially constant, this being arranged by making the cubic contents of tube 15 relatively negligible as compared with the cubic contents of bowl 7 less the Volume of fioat 8.

lt is understood of course that for a particular engine, the passages 12 and 17 may be a particular size calibrated for that engine, in which case the adjusting screws 13 and 18 may be dispensed with although the same are especially useful when testing.

Referring to Fig. 2, a rearrangement of the tubes 14, 15, and 16 is shown wherein the liquid fuel tube 16 is enlarged to receive a small central air tube 34 which communicates with atmosphere at its upper end through a plug 35 adapted to communicate with a passage 17 b forming an extension of passage 17 in the cross piece 2. The passage 17?) is adapted to be adjustably opened and closed by a valve 36 actuated by a thermostat 37 mounted on an insulated block 38 fastened to the outside of chamber 1.

` The plug 35 is adapted to hold 34 centrally and to substantially close the tube' 16 with the exception of a series of notches or grooves 39 around its perimeter and the interior of tube 34 communicates through a passage 40 with the interior of tube 15 and thus through orifice `25 with the passage 17 b. The operation of this modification is substantially as already described with the exception that a e constant current of air is now being drawn through passage 17 b, tube 14, tube 15 and passage 40, down through the tube 34 substantially to the bottom of the interior of tube 16 thence upwardly past the grooves 39 to the engine. The liquid fuel level in tube 15 will be caused to rise andfall as already described whereby Varying amounts of liquid 'uel will be drawn interiorly of pipe 16 where the same will be mixed with the ascending column of air and'drawn to the engine. In this manner a more rapid and steady feed of fuel and air mixture will be carried to the engine.

Referring to Fig. 4 'wherein my devioe is shown attached to the engine 32), a casing 41 is shown inserted between pipe 31 and passage 4 containing a fiap valve 42' preferably set in an enlarged portion of square cross sec-' tion. The valve 42 is mounted on a spindle 43 which extends through casing 41 and joined to arm 45, said arm and'valve 42 being restricted in their movement by spring 46 attached to casing 41 and arm 45. This valve 42 may be used when it is desi'red to use large size venturis 23 or 27 in which case the suction at their throats would be diminished `:for a given flow of air and is useful in accelerating from idling speed because it throws an 1ncreased suction on the discharge of 'tube 16 and passage 26 temporarily whereby increased accelerating charges of liquid fuel are drawn through orifices 24 and 25. An equivalent is a loose weighted valve mounted ofi' center as shown i`n an application executed of even date herewith. I

While it is understood of course that bowl 7 may be, and generally is, supplied with liquid fuel from a tankby gravity, or through the well known vacuum tank, at the same time the system herein described readily adapts itself to the automatic supply of liquid fuel from a low level to the bowl 7 at a high level and this is accompli-shed by establishing higher degrees of vacuum inside the bowl 7 and tube 14 while maintaining substantially the same pressure difl'erentials therebetween.

Referring particularly to Figs. 4 and 6, this may be accomplished by passing the feed pipe 47 direct from the passage 7?) to the bot tom of a liquid fuel tank 48 at a low level, the tank 48 being open to atmosphere through a port 49. The pipe 47, inside the tank 48, may contain a series of very small orifices 50 for lightening the rising columnof fuel as is well shown and described in my reissued Patent No. 14,701. In this case I provide that the uppermost orifice 50 will always be above v the normal liquid level in the tank 48..

Au extension 51 is provided on the side of cover 6 and extension 51 is drilled with a passage 52' adapted to communicate with the throat of venturi 27 and is adapted to receive ISO r l v.

a small venturi 53 the throat of which communicates through a passage 54 with the interior of bowl 7. The other end of passage 52 communicates' through a passage 55 with atmosphre. The venturi 53 may have what I am enabled to maintain a vacuum in the bowl 7 of from two to three -inches of mercury which is suflicient to .maintain the normal liquid level A--A and at the same time permit theproper functioning of the fuel regulator itself. 'This vacuum of *two to three inches of mercur is normally suflicient -*to supply an automobile engine with liquid fuel on a steep grade where wide open throttle conditions and the aforesaid vacuum need not be maintained constant but may vary .within limits provided not less than a minimum is developed. In Fig. 6 it will be notedalso that the valve 29 may be made adjustable in the i thermostat 28 by`.having a screw-threaded stern and 'a lock nut 58.

Referring to Fig. 5,' a modification' is` shown wherein the tube 14 is extended below the normal liquid* level A- A and the passage 26 is also 'brought below theliquid level to communicate with the interor of 14. Thus on accelerationadvantage is taken of 'the normal hydrostatic head to accelerate the discharge of liquid fuel through orifices 25 to the passage 26, which also may be controlled if desired by thermostat 28 and valve 29. Thepassage of air through pipe 26 in this case is brought through the wall of pipe 14' and through a Venturi 53 as already described, the throat' of said venturi communicating with the interior of bowl`7 through a passage 54:. Referring particularly to Fig. 7, an alternative Construction is shown wherein the thermostat 28-'will operate in a reverse direction, 'that is, it will operate to open the valve 29 with increasing temperature. In this case the valve 29 has anextension valve 59 attached ther-eto adapted to open and close an air passage 60 in the flange ofbowl 7 syn'- chronously with the opening and closing bf the valve 29 whereby increasing or decreasing amounts of air will be admitted to passage 26 to incre'asingly or decreasingly aflfect the height to which the liquid fuelwill recip- -rocate in tube 15, thereby giving an automatic fuel reguluti naccording to temperature.

The action of the liquid in the manometer comprising bowl 7 and tube 15 may, of course,

be used on any carburetor for the functions of priming and idling, provided the float chamber of the same is maintained under partial vacuum as described herein b sui-table connections to the mixing Cham er on the engine side of the throttle.

When idling the engine at optimum tem-` perature, the lowermost orifice 24 will pref'- erably be of correct size to supply the engine with just suflicient fuel at that tem erature. Such orifice will, of course, provi e insufficient fuel-for idling at low temperatures so that the manometric action will then supply additional fuel through one or more of the next succeeding lower orifices24. In general the lowermost three or four orifices 24 may be spaced to 'cut in or out at a change of 20 R P. M.`in engine speed When the engine is throttled from wide o en to closed throttle, it will be noted that t e liquid fuel will be drawn away from passage 26 thus preventing backfiring` in the muflier due to a rich mixture.

' While the new functions of my fuel regulation as applied to carburetors has been dei scribed, it must be box-ne in mind that a great Simplicity of Construction, with corresponding cheapness of cost, as well as economy in operation is attained.

It will thus be seen that the invention comprises the use of a rising and falling column of liquid fuel from which varying amounts are supplied to the engine dependng on the engine requirements through its suction and that the heads under which such varying amounts are supplied will vary' depending on the position of said column from which the same are drawn. The inertia of the reciprocating column is-valuable for giving increased supplies 'upon acceleration and this inertia may be incrcased as will be described in another application.

In general increasing amounts of liquid fuel are drawn fr`om a column increasing in length,- the volume of the column being maintained substantially constant and vice versa, while the liquid column remains unmixed with air. The thermostats 37 and 28 are mounted on insulating blocks 38 and 30 respectively in order that they should not be aflected by the heat abstracted fromthe carburetor casting by the latent heat of evaporation of the liquid fuel, but only affected by increasing or decreasing engine temperatures. Thus, it will beobvious that the thermostat 37 may also be 'enclosed in a casing and joined by a pipe to exhaust 33 as shown for thermostat 28 and also illustrated in said copending apr plications, Ser. Nos. 56,513 and 67 ,864.

' It is of course obvious that many combina- *tions and changes can be made in the structure as shown to get like results butall such changes are within the scope of the appended c ams. i

tion for maintaining the liquid fuel therein substantially'constant from a low level supply. 2. In a carburetin-g system for an internal combustion engine, a liquid fuel reservoir for the carburetor, means to raise and lower a a column of liquid *fuel from the reservoir through the carburetor, means including a thermostatically controlled valve to draw oil suficient fuel from the column for varying Operating conditions on the engine, means to apply engine suction to both ends of the column and means to maintain sufiicient vacuum in the reservoir for maintaining the liquid 'uel therein substantially constant from the low level supply.

3. In a carbureting system for an internal combustion engine, a liquid fuel reservoir for the carburetor, a liquid fuel supply at a lower level than the carburetor, means'to raise and lower a column of liquid fuel from the reservoir through the carburetor, means to draw oti' sufcient fuel from the column "for varying Operating conditions' on the engine,` a conduit jining said reservoir and said low level supply, means to maintain suflicient vacuum in the reservoir for maintaining the liquid fuel supply therein substantially constant through said Conduit from the low level supply and means to introduce air into said Conduit.

4:. In a carbureting system for an' internal combustion engine, a liquid :tuel reservoir for the carburetor, a liquid fuel supply at a lower level than the carburetor, means to raise and lower a column of liquid fuel from the reservoir through the carburetor, means to draw ofi suicient fuel from the column for varying Operating conditions on the engine, a Conduit joining said reservoir and said low level supply, means to maintain sufiicient vacuum in the reservoir for maintaining the liquid fuel supply thei'ein substantially con-i stant through said conduit from the low level supply and means to introduce air into said Conduit at a point above the normal liquid level in said now level supply.

5. A carburetor for internal combustion engines comprising a fuel chamber, an air passage, a plurality of venturi in said passage, means for supplying fuel from said fuel chamber to said venturi, and thermally operated means for controlling the supply of fuel to one of said venturi.

`venturi into said chamber, said pipe being closed at its upper end and open at its lowe*` end and having a plurality of openings in the side wall of its upper end portion, a

nozzle tube extending into said pipe, said nozzle tube being closed at its lower end and having a nozzle opening at its upper end and provided with a plurality of openings in its side wall, means for supplying air to said pipe, and means for maintaining said chamber at sub-atmospheric pressure.

7. A carburetor comprising a fuel chamber, an intake passage, a throttle in said passage, a pair of nozzles for supplying fuel to said passage, and a thermally controlled valve for controlling thesupply of fuel to one of said nozzles.

8. In a fuel feeding system for internal combustion engines, an intake passage, a float chamber connected to said passage, an outer tube closed at its lower end "and extending upwardly in said intake, an inner and an intermediate tube extending downwardly into said chamber below the normal liquid level therein and e'xtending u wardly in said outer tube, said inner tube heing closed at its lower end, having openings in its lower portion and provided with a nozzle opening at its upper end, said intermediate tube being open at its lower end and closed at its upper end and having air openings in its upper portion, said outer tube being in connection with the atmosphere, and a throttle for controlling the passage of air through said intake passage. a

9. A carburetor for an internal combustion engine comprising a mixing chamber, a venturi in said chamber, a fuel supply reservoir a nozzle tube ext/ending om the venturi into said reservoir, said tube being open at its upper end and closed at its lower end and having a vertical series of openings in its side wall, a second tube substantially coextensive therewith being closed at its upper end and open at its lower end, the upper end having openings in the side wall thereof,

athird tube surrounding the upper end of the second tube and communicating therewith through said openings in the wall thereof and means for applying a variable suction to said third tube to vary the fuel level in the second tube.

10. A carburetor for an internal combustion engine comprising a mixing chamber, a throttle valve at the intake of said chamber, a venturi in said chamber, a fuel su ply reservoir, a nozzle tube extending om the venturi into said reservoir, said tube being open at the end adjacent the venturi and' closed at the end in said reservoir and having a vertical series of openmgs in ts side wall, a second tube surrounding said nozzle tube closed at its upper end and open at its lower end, the upper end having ofienings in the side wall thereof, a, third tube enclosing the uppe end of the second tube and communicating with the second tube throgh the openings in the wall thereof and means responsive to the position of the throttle valve for varying the suetion in said third tube; thereby varying the fuel level .in the second tube.

Signed at Wihnington, in the county of Los Angeles and State of California, this 14th day of October, A. D. 1925. 15 CHARLES LAWRENCE STOKES. 

